Synthesis of high molecular weight poly(vinyl acetate) having less branched structure via photo-induced emulsion polymerization of vinyl acetate in the presence of poly(oxyethylene)(20) nonyl phenyl ether, a nonionic emulsifier, was attempted at 0degreesC or even below 0degreesC in the presence of methanol. It was found that 100% conversion is always achieved in all runs and poly(vinyl acetate) having the number-average degree of polymerization of 9000 with less branched structure (degree of branch < 0.5) can be obtained from this photo-induced emulsion polymerization system. Mechanisms of the polymerization were also discussed on the basis of the kinetic results.